Police radar units or guns have two different modes, depending on the device.

Moving Mode: Can be used when the police vehicle is moving towards or away from the target vehicle (soon to be defendant). Moving police radar have a higher, user (police officer) error(s) than other modes.

Stationary Mode: Is only used when the police vehicle is parked. The operator (police officer) can aim the antenna towards the area of target vehicle (soon to be defendant). Although, stationary mode has a lower error rate versus the moving mode, it can still have double digital ratio error rate.